LOS ANGELES – Hundreds of law enforcement officers Friday raided Southern California auto parts shops and other businesses suspected of illegally selling nitrous oxide for use as a recreational drug, in one of the nation’s largest such raids to date.

Four federal arrest warrants were served during the 17 simultaneous raids in Los Angeles, Orange and Riverside counties, and at least two people were arrested on misdemeanor charges of misbranding a drug in violation of the federal Food, Drug, and Cosmetic Act. Authorities said they expected more arrests to come.

The operation was the result of a year-and-a-half-long joint investigation dubbed “No Laughing Matter” by the Food and Drug Administration’s Office of Criminal Investigations and the Los Angeles County Sheriff’s Department.

The FDA has recently focused on the illegal use of nitrous oxide, and this was its largest case to date, said special agent Lisa Hartsell. Though nitrous oxide has long been a rave phenomenon, it has recently grown into more mainstream use, propelled by the ease of social media to reach young people and spread the word.

“This is a very cheap drug, can be had very easily, it is not a controlled substance, so your big members of the law enforcement community don’t have the ability to control it,” Hartsell said.

The gas is legally used by dentists for anesthesia, to pressurize whipped cream canisters and to speed up race cars. But authorities say its illegal use has spurred fatal car accidents, rapes and teen deaths — all in the name of a temporary high.

Los Angeles County sheriff’s officials have zeroed in on the recreational use of the drug since September, cracking down on more than 350 illegal parties, nearly all of which were selling nitrous oxide, or “noz,” spokesman Mike Parker said Thursday.